The present invention relates to an improver for bone metabolism, which comprises chain isoprenoid fatty acid esters as the active ingredient, which is excellent in the bone metabolism-improving effect and absorbability, safety and which is advantageous in the price and the present invention also relates to a food or beverage for the improvement of the bone metabolism.
Recently, the average span of life of the human being has gradually been increased due to the progress in, for instance, medical science. Correspondingly, in the society having a high rate of aged persons, which is attendant on the increase of the span of life, how to spend and enrich the life in the senescence (the quality of life) would be quite important for the aged persons. To enrich their life, it is essential that the aged persons are sound in their minds and bodies and, to this end, it is a key or principal subject to develop any means for impeding or arresting the aging. There have been described a variety of aging phenomena based on the foregoing standpoints and the osteoporosis as a representative senile disease has attracted special interest recently. In particular, the osteoporosis is a systemic disease in which the bone gets fragile and the patient attacked by the same easily suffers a fractured bone. This would be a disease, which constitutes a variety of social problems. For instance, this may correspondingly cause the fracture of collum femoris and the compression fracture of the spine, which are accompanied by severe pains, and the patient may become a bedridden (old) man because of such a fracture of bone.
In the normal condition, the bone always repeats remodeling thereof to thus maintain the equilibrium in the bone metabolism. More specifically, the bone is replaced with fresh one with a period ranging from 120 to 150 days, without accompanying any change in the amount thereof, while maintaining a good balance between the system (bone absorption system) for destroying and absorbing tissues, which are calcified by the osteoclasts for the supplementation of the calcium component required for the life conservation activities from the bone to the blood and the system (osteogenesis (bone forming) system), in which the osteoblasts and osteocytes deposit collagen and/or calcium, as bone substrates, onto the bone. In the osteoporosis, however, there exists abnormality in such bone metabolism or the bone absorption ability gets ahead of the osteogenetic function and this may lead to the reduction in the amount of the bone and the bone gets fragile. In particular, in the women after their menopause, the function of secreting and forming the female hormone, which has a bone absorption-inhibitory action and an osteogenesis-promoting action, is rapidly impaired and accordingly, they are quite susceptible to the abnormality in the bone metabolism and they lose their balance between the bone absorption ability and the osteogenetic function. For this reason, they are liable to suffer from the osteoporosis. In fact, one out of three women of 45-year-old or older has already suffered from the osteoporosis or the considerable reduction in the amount of the bone. Therefore, materials having an effect of improving or eliminating such abnormality in the bone metabolism may be expected as prophylactic agents or therapeutic agents for the diseases related to bone such as osteoporosis.
It has previously been recommended to ingest a sufficient amount of calcium, vitamin D and vitamin K in the form of a diet from the viewpoint of the improvement of the bone metabolism and the prevention of osteoporosis. At present, however, one should care about his eating habit in order to efficiently ingest these nutrients and only persons who fear to suffer from such diseases have improved their eating habit. Moreover, these nutrients have also commercially been supplied or distributed in the form of health foods such as tablets and supplements, but there have not yet been solved many problems concerning, for instance, absorbability, stability and price of these nutrients. In view of the present status, there has been desired for the development of a material, which has a bone metabolism-improving effect and an osteoporosis-prophylactic effect, which can efficiently be absorbed, which is stable and which can be provided at a low price.
Up to now, there have been developed, for instance, Estrogen, Calcitonin, Ipriflavone, activated vitamin D3, Bisphosphonate and Vitamin K2 as therapeutic agents for treating the osteoporosis. However, these conventional therapeutic agents suffer from a variety of drawbacks or cause various harmful side effects, respectively. For Instance, the administration of Estrogen results in bleeding like the menstruation (false menstruation), becomes a cause of some unpleasant feelings such as swelling of the breast and may increase the incidence of a disease such as breast cancer (mastocarcinoma). Calcitonin is a peptide and it can only be administered through injection. The administration of Ipriflavone may bring about gastro-intestinal disorders. Activated vitamin D3 may induce hypercalcemia and may cause urolithiasis and disorders of digestive organs. The administration of Bisphosphonate may likewise inhibit the osteogenetic function of patients. Vitamin K2 also shows a blood coagulation effect and therefore, the administration thereof is limited to specific patients. In addition, all of these therapeutic agents are not sufficient in the establishment of the balance between the efficacy as pharmaceutical agents and the convenience or their price. For this reason, there has recently been focused attention on the development of novel pharmaceutical agents and foods and beverages developed from such standpoints.